How to slice a video at camera angle changes

Question

I have a long live feed recorded.

It has different camera angles switching after one another but unpredictable timing.

The cameras do not zoom or move so what is recorded has parts that don't change that could be used to identify camera angles. There should be a way to cut the film into small segments and group them by angle.

I could do this using iMovie by hand but that would take forever as I would like to do this for many hours of this live feed.

Is there a way to do this using some free software?

Answer 1

To correctly detect the scene changes (almost correctly some changes were still not detected) I used Davinci Resolve. Then I had to type the wanted scene's start frame and end frame into a program that automatically cut it.

From Davinci Resolve it was extremely hard to copy the frame numbers as they could not be selected. I am sure there is a better way of getting the start frames and end frames from Davinci Resolve but I couldn't find it.

The cutting can be done using ffmpeg:

ffmpeg -i example.mp4 -vf trim=start_frame=10:end_frame=50 -an -fflags +genpts output.mp4

But it takes really long to get a clip from the end of a long movie for example.

It can also be done using applescript and that is much faster:

tell application "QuickTime Player"
    activate

    set startFrame to 84361
    set endFrame to 84452

    set fps to 23.976

    set startTime to startFrame / fps
    set endTime to endFrame / fps

    set inFile to "Users:me:Documents:folder:infile.mov"
    set outFile to "Users:me:Documents:folder:outfile.mov"

    try
        set theOpenedFile to open for access file outFile with write permission
        set eof of theOpenedFile to 0
    end try

    open file inFile
    trim front document from startTime to endTime
    export front document in outFile using settings preset "1080p"

    try
        close access theOpenedFile
    end try

    close every document saving no
end tell